Coking process



Dec. 7, 1965 A. NAGELVOORT comm rnocmss Filed Jan. 10, 1963 INVENTOR.ADRIAN NAGELVOORT ATTORNEYS States Patent 3,222,261 COKING PROCESSAdrian Nagelvoort, Los Altos, Calif assignor, by direct and mesneassignments, to Complex, Incorporated, Menlo Park, Califi, a corporationof California Filed Jan. 10, 1963, Ser. No. 250,516 Claims. (Cl. 202-17)This invention relates to the preparation of coke and more particularlyto an improved system and method of preparing coke from coal.

In the past, coal has been converted to coke by batch processes such assteam distillation. In steam distillation, lump coal is fed into anautoclave where steam under high pressure and high temperature isapplied. The volatiles of the coal, together with the steam, are drainedofi gradually. The coke is left within the autoclave long enough tocomplete the coking process. A process such as this takes from twelve totwenty-four hours. Another batch process requiring comparable timeemploys ovens with externally applied heat.

It is a general object of the present invention to provide an improvedmethod and means for converting coal to coke.

It is a more particular object of the present invention to provide animproved means and method of quickly converting coal to coke.

It is yet another object of the invention to provide a simplifiedcontinuous method and means for converting coal to coke.

These and other objects of the invention will be pointed out in thefollowing description and claims and illustrated in the accompanyingdrawing, which discloses, by way of example, the principle of theinvention and a preferred mode which has been contemplated of applyingthat principle.

In the single figure of the drawing, there is shown schematically asystem for converting coal to coke according to the invention.

Generally, according to the invention, there is provided a method ofcoking crushed coal which includes the steps of directing a stream ofsuper-heated steam under pressure along an inclined enclosed passage ofpredetermined extent, introducing coal into the stream at the lower endof the passage so as to release volatiles from the coal and convert thecoal to coke for discharge at the elevated end of the passage. The angleof incline of the passage and the pressure of the steam are such as topermit transport of the lightened coke material by the stream along thepassage to the substantial exclusion of the unconverted coal, so as toseparate the former from the latter. As the coke is discharged from thepassage, it is collected.

According to a preferred method, coal such as bituminous coal, iscrushed to a size which will pass a ring of the order of 7 inch. Thecrushed coal is introduced into an enclosed and substantiallyunobstructed passage inclined at a predetermined angle on the order offive or six degrees. The passage is open at the elevated end so as todischarge material from the passage. superheated steam under pressure isinjected into the lower end of the passage so as to convert the coal tocoke and transport the latter up the passage.

With reference to the figure, there is provided means forming anelongated enclosure having a substantially unobstructed insulatedpassage therealong which is inclined at a predetermined angle. Thus, inthe drawing, the enclosure structure includes an elongated portion 10which includes a substantially cylindrically shaped metal liner 11surrounded by insulation 12 and enclosed by an outer wall 13. The liner11, therefore, forms a substantially unobstructed passage extendinglongitudinally of the portion ice 10. Liner 11 is disposed at an angleon the order of five or six degrees to the horizontal by supports 14 and15, schematically shown.

Means are provided which serve to direct a stream of superheated steamunder pressure, into and upwardly along the liner 11. Said meanscomprises steam line 16, valve 17 and steam line 18, having a pressurerelief valve 19 therein. A superheated steam boiler is represented bythe chamber 21 including a plurality of turns of the steam line 22 whichconnects with line 18. A plurality of burners 23 are schematically shownfor forming steam in line 22.

Means are provided serving to continuously direct crushed coal into theinjected stream of steam at a lower region of the inclined passage. Inthis manner, volatiles are released from the coal by heat from thesteam. The means for delivering the coal can include a conveyor such asendless belt 24 driven to discharge crushed coal into a bottom openinghopper 25, through a one-way valve 26 into liner 11. Valve 26 is ofsuitable construction whereby coal is permitted to pass into liner 11without substantial loss in pressure of the applied steam.

The enclosure further includes a trap portion 27 formed as a hopper-likechamber wherein one wall 28 is disposed to form a sill 29 with respectto the discharge opening 30 at the elevated end of liner 11. The bottomof trap portion 27 is formed with a port 31 which is in communicationwith the inlet end of a motor driven screw conveyor 32 arranged totransport coke from trap portion 27 continuously from left to right asshown in the drawing. Heat exchange means 33 for preheating feed waterto the system is shown whereby the heat from coke collected in trapportion 27 is recovered to the system. As thus arranged, conveyor 32discharges coke to pass downwardly through the coils 34 of heat exchangemeans 33 and out the bottom at 35. Coils 34 are connected at one end toa feed water pump 36, pumping feed water from a reservoir into coils 34to supply same in heated condition to line 22 via the valve 37.

At the upper region of trap portion 27, there is provided an outlet 38whereby the vapors and volatiles pass to a condenser means 39 serving torecover volatiles entrapped in the steam, for example, such as tar, etc.

Operation of the system shown in the drawing is as follows: Coal iscrushed to a size on the order of *3 ring mesh and is transported byconveyor 24 for introduction into the elongated passage 11. Superheatedsteam is generated in chamber 21 and injected upwardly along theinclined passage through the raw coal in liner 11.

In one example, the coal was bituminous, crushed to pass a ring mesh,and the temperature of the steam was 850 C.

The steam injected through the coal serves to release substantially allthe volatile constituents rather quickly in the hot atmosphere. With a16 Particle size, penetration of heat into the center of the particle iseffected very quickly. As the steam agitates the deposit of coal withinpassage 11, the lower specific gravity of coke as it is formed serves toseparate it from the coal and move it more quickly upwardly along theinclined passage. Thus, the coke is carried along or entrained in thestream of steam faster and farther than the uncoked coal and the angleof incline serves to separate the coke from the coal. It is believedthat as the coal is converted to coke, it absorbs heat at first untilthe major part of the volatiles have been broken down. At this point, anexothermic reaction is believed to take place which hastens the cokingprocess and finishes it off quickly.

As the coke reaches the trap portion 27, it passes over sill 29 and, dueto the slight drop in velocity caused by 3 enlargement of the enclosure,falls into the inlet end of conveyor 32. Conveyor 32 then transports thecoke from left to right as shown in the figure until it is dischargeddown through heat exchange means 33 where the heat of the coke serves topreheat feed water being pumped along line 34.

The released volatiles and steam vapor escape along the upper region oftrap portion 27 via outlet 38 into a condenser 39 where the volatilesare recovered as a byproduct. By using steam distillation, the cokingtemperatures are able to be much lower than in a standard cokingprocedure where heat is applied from the outside.

Inasmuch as the steam pressure is just enough to overcome the backpressure from the released volatile vapor as well as to carry the solidparticles up the incline, it will be readily apparent that variousangles of incline will cause variations in the pressure required.Furthermore, it will be equally obvious that the extent of the elongatedpassage 11 necessary for complete coking will vary to some degree withthe temperature of the steam being utilized. Accordingly, the aboveexample is considered exemplary only and the invention is to be limitedonly by the scope of the following claims.

I claim:

1. In a process of coking crushed coal, the steps of introducing thecrushed coal into an enclosed and substantially unobstructed passageinclined at a predetermined angle, said passage being open at theelevated end to discharge material therefrom, injecting super-heatedsteam under pressure into the lower end of said passage to coke the coalthereby reducing its density, and to transport the coke formed, to thesubstantial exclusion of the coal, up said passage faster and fartherthan the coal, and collecting said coke substantially exclusive of coalfrom the elevated end of said passage.

2. A process of coking crushed coal as defined in claim 1 wherein thevelocity of said steam in said passage with respect to the density ofthe coke is sufficient to transport the coke up said passage while beinginsufficient to so transport the coal, said coal being held back by theangle of incline of the passage.

3. In a process of coking coal as defined in claim 1 wherein the coal iscrushed to a size to pass on the order of a & inch ring mesh.

4. Apparatus for preparing coke from coal comprising an enclosureincluding an elongated portion forming a substantially unobstructedpassage extending therealong, said portion being formed to incline saidpassage at a predetermined angle to the horizontal, said portion havingan opening in the elevated end of said passage, insulation around saidelongated portion, said enclosure further having a trap portion disposedin communication with said opening, said trap portion including ahopper-like chamber having a wall thereof disposed to form a sill withrespect to said opening, said chamber having an outlet adapted toexhaust gases therethrough, the bottom of said chamber having a porttherein adapted to pass coke therethrough, means disposed at a region insaid elongated portion remote from said opening for introducing coalinto said passage, and means for injecting a continuous stream ofsuper-heated steam under pressure into said passage to release volatilesfrom said coal and convert said coal to coke whereby said coke isseparated by density from the coal and transported up said passage andinto said chamber to the exclusion of the coal and whereby saidvolatiles are entrained by said stream to pass via said outlet to beexhausted from said trap portion.

5. A closed system for preparing coke from coal comprising the apparatusdefined in claim 4 further including heat exchange means disposed withrespect to said steam injection means to transfer heat thereto from cokepassing through said heat exchange means, and conveyor means interposedbetween said port and said heat exchange means to transport coke fromsaid trap portion to said heat exchange means whereby heat lost duringcooling of said coke is regained by said system.

References Cited by the Examiner UNITED STATES PATENTS 2,586,703 2/1952Odell 202--17 FOREIGN PATENTS 104,346 6/1938 Australia. 119,040 2/ 1919Great Britain.

MORRIS O. WOLK, Primary Examiner.

1. IN A PROCESS OF COKING CRUSHED COAL, THE STEPS OF INTRODUCING THECRUSHED COAL INTO AN ENCLOSED AND SUBSTANTIALLY UNOBSTRUCTED PASSAGEINCLINED AT A PREDETERMINED ANGLE, SAID PASSAGE BEING OPEN AT THEELEVATED END TO DISCHARGE MATERIAL THEREFROM, INJECTING SUPER-HEATEDSTEAM UNDER PRESSURE INTO THE LOWER END OF SAID PASSAGE TO COKE THE COALTHEREBY REDUCING ITS DENSITY, AND TO TRANSPORT THE COKE FORMED, TO THESUBSTANTIAL EXCLUSION OF THE COAL, UP SAID PASSAGE FASTER AND FARTHERTHAN THE COAL, AND COLLECTING SAID COKE SUBSTANTIALLY EXCLUSIVE OF COALFROM THE ELEVATED END OF SAID PASSAGE.
 4. APPARATUS FOR PREPARING COKEFROM COAL COMPRISING AN ENCLOSURE INCLUDING AN ELONGATED PORTIONNFORMING A SUBSTANTIALLY UNOBSTRUCTED PASSAGE EXTENDING THEREALONG, SAIDPORTION BEING FORMED TO INCLINE SAID PASSAGE AT A PREDETERMINED ANGLE TOTHE HORIZONTAL, SAID PORTION HAVING AN OPENING IN THE ELEVATED END OFSAID PASSAGE, INSULATION AROUND SAID ELONGATED PORTION, SAID ENCLOSUREFURTHER HAVING A TRAP PORTION DISPOSED IN COMMUNICATION WITH SAIDOPENING, SAID TRAP PORTION INCLUDING A HOPPER-LIKE CHAMBER HAVING A WALLTHEREOF DISPOSED TO FORM A SILL WITH RESPECT TO SAID OPENING, SAIDCHAMBER HAVING AN OUTLET ADAPTED TO EXHAUST GASES THERETHROUGH, THEBOTTOM OF SAID CHAMBER HAVING A PORT THEREIN ADAPTED TO PASS COKETHERETHROUGH, MEANS DISPOSED AT A REGION IN SAID ELONGATED PPORTIONREMOTE FROM SAID OPENING FOR INTRODUCING COAL INTO SAID PASSAGE, ANDMEANS FOR INJECTING A CONTINUOUS STREAM OF SUPER-HEATED STEAM UNDERPRESSURE INTO SAID PASSAGE TO RELEASE VOLATILES FROM SAID COAL ANDCONVERT SAID COAL TO COKE WHEREBY SAID COKE IS SEPARATED BY DENSITY FROMTHE COAL AND TRANSPORTED UP SAID PASSAGE AND INTO SAID CHAMBER TO THEEXCLUSION OF THE COAL AND WHEREBY SAID VOLATILES ARE ENTRAINED BY SAIDSTREAM TO PASS VIA SAID OUTLET TO BE EXHAUSTED FROM SAID TRAP PORTION.